Tool carrier



Aug- 21, 1952 F. I-I. cuLvER ETAI. 3,050,130

Toor. CARRIER Filed April 20, 1959 HIS AGENT United States Patent O3,050,130 TOOL CARRIER Frederick Howard Culver, McAllen, and Edward B.

Lagucki, Houston, Tex., assignors to Shell Oil Company, a corporation ofDelaware Filed Apr. 20, 1959, Ser. No. 807,708 6 Claims. (Cl. 166-153)This invention relates to apparatus adapted to move an object through apipe and pertains more particularly to a tool carrier adapted to move atool, instrument, or other piece of equipment through a pipe string forexample through the flowline and tubing string of an oil well.

During the drilling, completion, servicing and/ or reconditioning of oilwells many objects such as sections of tubular goods, strainers,bottomhole chokes, tools, surveying and logging instruments, etc., mayfrom time to time be introduced into and positioned at a predeterminedlevel within either the well tubing or the well casing. These objectsare either dropped in the well so that they fall to a predeterminedposition by gravity, or they are lowered to the desired position on awire line, or they are pumped into position. In pumping a tool intoposition within an oil well, the tool is generally provided with apacker or sealing means surrounding it of a diameter equal to that ofthe tubing string through which it is to be pumped. After putting thetool in the tubing string, a uid is pumped down the tubing string inback of it, with the iluid already in the tubing or in the oil wellbeing circulated up the annular space between the tubing string and thewell casing.

In the event that it is desired to retrieve the tool from the bottom ofthe well and remove it from the well, the flow of fluid into a well maybe reversed so that the ow enters the annular space between the wellcasing and the well tubing, passing down through the well to the bottomof the tubing and up the tubing string, driving the tool ahead of it upthe tubing to the top of the well. Alternatively, a wire line with a`fishing head may be lowered into the well to connect with the top ofthe tool and later remove it from the well by pulling it upwardly by thewire line, in a manner well known to the art. Various methods ofintroducing and removing objects from a well are described in U.S.Patents 2,805,718, issued September 10, 1957, and 2,810,442, issuedOctober 22, 1957, to G. H. Tausch.

One drawback with the method of circulating a well tool or other pieceof equipment in and out o-f a well is that the packer or sealing elementcarried by the tool, or by any retrieving tool sent to latch on to awell tool, is subject to wear due to the frictional contact between thesealing element and the inside wall of the tubing string. Thus it may bereadily seen that if a tool and its packer is circulated to the bottomof a 10,000-foot well, considerable wear may take place on the packer sothat by the time the tool and the packer reaches the bottom of the wellthere is no longer a perfect seal between the packer and the inside wallof the tubing string. 'I'his is especially true in the event that atubing string is used having upset ends with exposed threads or a smallspace `between adjacent sections of the inner wall. Destruction off theseal between the packer and the tubing wall makes it diicult if notimpossible later to circulate the packer and its tool upwardly to thetop of the well. Additionally, without a perfect seal between the packerand the tubing wall at all times, it is impossible to determine theposition of the tool in the well during either its upward or downwardtravel. On the other hand, with a perfect seal between a packer and thetubing wall, the position of a tool or instrument being circulated downthe well may be known at any time by measuring the number of gallons ofdriving 3,050,130 Patented Aug. 21, 1962 ICG iluid being pumped into thewell to -force the packer and its tool or instrument one direction orthe other.

It is therefore a primary object of the present invention to provide anapparatus for moving a tool, instrument or other object to apredetermined position within a pipe.

Another object of this invention is to provide an apparatus for moving atool, instrument -or other object through a pipe while at the same timemaintaining a perfect seal within the pipe at all times.

A further object of the present invention is to provide an apparatusincluding sealing means which are designed to maintain a perfect sealwithin a pipe when passing therethrough, said sealing means beingadapted to compensate for any wear on the outer surface thereof.

Still another object of this invention is to provide an apparatus havingdual sealing means adapted to be selectively actuated when being runinto and out of ya well so that a diierent sealing element is used whenthe apparatus is run in opposite directions.

A still further object of this invention is to provide a exible toolcarrier adapted to pass around bends in a pipe, said carrier beingprovided with selectively inflatable sealing elements, one of which isinliated to maintain an eifective seal within a tubing string as thetool carrier is pumped therethrough, with the seals being adapted Itoexpand continually to compensate for any lwear on the outer surfacethereof.

These and other objects of this invention will be understood from thefollowing description with reference to the drawing, wherein:

FIGURES 1 to 4 are diagrammatical views taken partially in longitudinalcross-section of different Aforms of a tool carrier or tool pusher inaccordance with the present invention. The two carriers in FIGURES 3 and4 are shown as moving upwardly in la pipe.

Referring to FIGURE 1 of the drawing, a tool carrier constructedaccording to the present invention is shown positioned in a verticalsection of tubing such as employed in an oil well. The tool carriercomprises la central mandrel 11 on which are mounted a pair of sealingelements or packers 12 and 13 which surround the central mandrel 11 andare held thereon by suitable sealing-element or packer-retaining cups orrings 14 and 15, 16 and 17, respectively. The sealing elements 12 and 13and their retaining cups 14, 15, 16, and 17 are held in position on themandrel 11 by retaining nuts 18 and 19.

Preferably the mandrel 11 is provided with a iiexible linkage such as aball-in-socket joint 21 at a point between the sealing elements 12 and13 so as to facilitate movement of the tool carrier in curved sectionsof a well tubing or pipe. Since the possibility always exists that anytool attached to the tool carrier may become stuck in a well, the toolcarrier is preferably provided with a iishing head 22 whereby aretrieving tool (not shown) attached to the bottom of a wire line may belowered through the tubing string 10 to latch onto the rishin'g head 22,thereby allowing removal of the tool carrier by an upward pull on thewire line. n

As illustrated, the packer retaining elements or cups 14 and 15 surroundthe ends of the packer or sealing element 12 while at the same timebeing axially spaced from each other on the central mandrel 11 so thatthe packer element 12 is against, or may be expanded against, the innerwall of the tubing 10 to form a seal thereagainst. Preferably, thesealing elements 12 and 13 are formed having an internal diameterslightly larger than that of the mandrel 11 so that an undercut portionor annular space 23 is formed between the mandrel and the sealingelement 12.

Fluid ports 24 and 25 are provided through the walls of the packerretaining cups 15 and 17 near t-he closed ends thereof so that fluidpassageways are formed through the packer retaining cups incommunication between the space outside the packer and the annular space23. Since the sealing element 12 of FIGURE 1 may during use be caused torotate slightly with regard to its retaining cups 14 and 1S, it ispreferably designed so that the closed end of the cup terminates aboveport 24 so that the fluid passageway is maintained at all times incommunication between the inside of the sealing element 12 and the spaceoutside the tool carrier.

The packers or sealing elements 12 and 13 are made of any suitableinflatable resilient material such -as rubber, synthetic rubber,rubberized fabrics or certain plastic materials which may be expandedunder the application of fluid pressure. The portion of the sealingelement 12 in contactwith the inner wall of the tubing may have athickened cross-section so as to provide for some wear on the seal as itis propelled through the tubing. In addition, the sealing element 12 maybe bevelled to substantially a point, as illustrated, if desired.

Preferably, the sealing element 12 is formed so that its lower end,i.e., the end farthest from fluid port 24, fits closely about thecentral mandrel 11 near the lower retaining cup 14 in a luidtightmanner. In the event that the packer 12 does not have a tight fit atthis point, an O-ring seal 26 may be positioned between the retainingcup 14 and the mandrel 11.

When the tool carrier of the present invention is to be used to run atool or instrument down a well tubing 10, the present tool carrier orpusher may merely be in touching engagement with the tool to beinserted, or alternatively may be fixedly secured to the tool in anysuitable manner as by screw threads or, if desired, detachably connectedby spring clips or other readily detachable latching means. In running atool to the bottom of a well the tool would first be inserted in the topof the fiowline and tubing with the present tool carrier forced inbehind it. The top of the tubing would then be closed and tiuid pressurewould be applied to drive the tool and its tool carrier down to thebottom of the well. When pressure is applied above the tool carrierillustrated in FIGURE l, the pressure fluid flows past sealing element13 and enters fluid ports 24 and 25 leading to the sealing elements 12and 13, respectively. Since the fluid pressure on either side of thebevelled sealing element 13 would be the same there would be no tendencyfor the sealing element 13 to expand against the wall of the tubing 10to form a tiuidtight seal thereagainst.

The pressure fiuid entering fluid port 24 would pass down into theannular space 23 and force the sealing element 12 against the inner wallof the tubular member 10 so that the lower sealing element 12 would actas a piston to be forced downwardly through the tubing string 10 by theapplication of further pressure uid above it. This action takes placesince a usable pressure differential exists across the lower sealingelement 12 of FIGURE 1 whereas no usable pressure differential existsacross sealing element 13 on downward travel of the tool carrier. Thusit may be seen that, on the downward travel of the present tool carrier,the upper sealing element 13 would merely be a follower-piston whichwould not contact the tubing wall with any force to form a sealthereagainst and hence would not be subject to wear as the tool carrierpasses downwardly through the tubing string 10. With the lower packer 12maintaining a tight fit in the tubing string 10 at all times, theprecise location of the tool carrier or pusher can be determinedaccurately at any time from a measure of the amount of pressure fluidinjected or pumped into the top of the tubing string 10.

To return the tool carrier, with or without its accompanying tool (notshown), circulation of the driving fiuid in the well is reversed so thatthe pressure fluid would pass downwardly outside the tubing string 10and upwardly through it. Thus the action of the sealing elements 12 and13 would be reversed with sealing element 13 acting as the piston, andsealing element 12 acting as the follower.

In the event that the tool carrier is sent down to the bottom of theWell to retrieve a tool, instrument, or other object therein, the toolcarrier is provided with suitable latching means 27, well known to theart, which may take the -form of the one described in U.S. yPatent1,700,- 324, issued January 29, 1929, and entitled Letting-In Tool forOil and Gas Well Appliances. This latching device 27 would normally befixedly secured to the central mandrel 11 in any suitable manner, as byscrew threads. Thus upon circulating the present tool carrier downwardlyto the bottom of a tubing string it would latch on to the top of thetool, instrument, or other object therein and, upon reversing thecirculation of the fluid in the well would pull the tool or other objectupwardly with it when the tool carrier was circulated to the surface.

While the present tool carrier has been illustrated as having a sealingelement 12 acting as a leading piston with a follower uninllated sealingelement behind it, it is realized that the sealing elements of the toolcarrier could be turned end to end as illustrated in FIGURE 2, in whichcase the sealing element 13a first exposed to upstream pressure wouldserve as the piston which would push ahead of it the uninfiated seal-ingelement 12a on the downward trip tinto the well. On the upward trip theactions would be reversed with the lower packer 12a acting as the pistonand pushing ahead of it the upper sealing element 13a. It is essentialthat one of the fluid ports, say port 25a, of one sealing element 13a beposi-v4 tioned on the downstream side thereof when positioned within theflow stream within a pipe, while port 24a of the other sealing elementis positioned upstream. In this case the fluid pressure is considered asbeing applied upwardly through the tubing 10.

An alternative arrangement of the present tool is shown in FIGURE 3 withparts similar to those of FIGURE l, the main difference being that thetool of FIGURE 3 is not provided with a fishing head 22 or latchingmeans 27, as shown in FIGURE l, In this arrangement the packers 12b and13b `are mounted on tubular mandrels 11b and 9b, respectively. The endsof the packers or sealing elements 12b and 13b are held firmly in placeby the retaining cups 141;, 15b, 16b, and 17b. The space 2311 is incommunication with the space outside the packer 12b through port 24h,bore 28b and port 29b. It is evident from the construction of the toolof FIGURE 3 that, in the absence of any means for attaching the presentapparatus to a tool or instrument, etc., the present apparatus can onlybe used to push a tool, instrument, etc., into place.

The arrangement shown in FIGURE 4 of the drawing is merely one-half ofthe apparatus shown in FIGURE 3 without the swivel joint 2lb of FIGURE3. This tool may be employed as a one-way pumpable barrier, in the eventthat it is not desirable to return the apparatus to its starting point.It is essential that all of the packers 12, 12b, and 121,` be firmlysecured at their ends by means of retaining cups which prevent thepressure of the fiulid stream from opening the packer up to an extentsuch that the fiexible packer member 12ol is caused to turn inside out.Thus in many present tools, an unrestrained swab cup arrangement isundependable because the edges of the cups, facing the direction inwhich the device is to be moved, often catch on the irregularities inthe pipe wall, for example in the pipe joints, and furthermore the edgesare often folded back over their sides where they are quickly damaged toa point of being inoperable.

Field operations with the present apparatus has established that it isuseful in at least two types of tube cleaning operations for removingsolids adhering to the interior of a pipe string positioned within anoil well. The present apparatus can be effectively used in removingparafiin from well tubing. In pumping the present apparatus down aparaliin-laden production string, most of the paraffin is pushed aheadof the apparatus into the heated zone near the well bottom where theparaffin is melted and re-entrained in the well production fluid.

On return of the present apparatus to the top of the well, bycirculation 1in a manner herein described above, additional portions ofthe thin film of parain left on the interior wall of the tubing arepushed ahead of the present apparatus, and the warm paraflin entrainedin the fluid immediately behind the present apparatus is moved throughthe tubing in a manner which inhibits or reduces the redeposition ofsolid paraffin in the cooler regions traversed by the tubing string.

The present apparatus can be similarly effective in removing hydrocarbonplugs which tend to form in tubing strings and owline in whichproduction uids from high gas ratio wells are conveyed through zones inwhich the temperatures are low relative to that of the produced lluid.The formation of these rather complex hydrocarbon solids is ananticipated problem in underwater wells in which the production tubingstring and owline are exposed to ocean floor temperatures in the orderof 40 to 50 F.

The present appar-atus is also particularly useful in insuring that aselected portion of a pipestring is contacted by the treating tiuid,such as a corrosion inhibitor or a solvent. In field operations it hasbeen established that the slippage of the driving uu'd past the presenttype of barriers is extremely small. For example, the metering of theamount of iiuid used in pumping the barrieralong the pipe stringprovides an accurate prediction of the time of arrival of the tube at Aastop or a sharp bend which has a known location and produces a knownfluctuation in the uid pressure. Since the slippage of fluid past thepresent apparatus is minor when a volume of treating fluid is introducedinto a pipe string ahead of the present type of barrier and both arepumped to the bottom of a pipe string, the treatment of the entirelength of pipe string can be definitely established. A barrier -inaccordance with the present invention can be left in the tubing stringto be circulated out by the production fluid of the well or can beimmediately removed by pumping the fluid through the pipe string lin theopposite direction. lf a single barrier in -accordance with FIGURE 4 isto be employed, -it is essential that the length of the barrier or itsmandrel 11c be greater than the inside diameter of the pipeline throughwhich itis to be pumped so that the barrier will not tilt within thepipe and lose its seal. In the case of a single barrier as shown inFIGURE 4 it is essential that the shape of the packer 12C and the lengthof the central mandrel 11c be such that a seal is maintained at alltimes with the pipe wall.

We claim as our invention:

1. Apparatus adapted to be pumped through a pipe, said apparatuscomprising a body element mandrel of a diameter smaller and a lengthlonger than the diameter of the pipe through which it is to be pumped inan unsupported manner, expandable annular sealing means carriedco-axially on said mandrel, retaining means fixedly securing oppositeends of the sealing means to said body element mandrel, and fluidpassage means through said apparatus in communication between the insideof said seal means and the outside of said apparatus near one endthereof the other end of said body element mandrel being closed at alltimes.

2. Apparatus adapted to be pumped through a pipe, said apparatuscomprising a mandrel element of a diameter smaller than the pipe stringthrough which it is to be pumped in an unsupported manner, yat least apair of selectively expandable annular sealing means carried 6h saidmandrel in axially spaced relationship, and separate iiuid passage meansin said apparatus adjacent each of said sealing means in communicationbetween the inside and outside thereof, the opening of said liuidpassage means to one sealing means being positioned on the upstream sidethereof when positioned in a flow stream within a pipe, while that tothe other sealing means is positioned on the downstream side thereof.

3. Apparatus adapted to be pumped through a pipe, said apparatuscomprising a mandrel element of a diameter smaller than the pipe stringthrough which it is to be pumped in an unsupported manner, at least apair of selectively expandable annular sealing means carried on saidmandrel in axially spaced relationship, separate fluid passage meansinsaid apparatus adjacent each of said sealing means in communicationbetween the inside and youtside thereof, the opening to said iluidpassage means of one sealing means being positioned on the upstream sidethereof when positioned in a ow stream within a pipe, while that to theother sealing means is positioned on the downstream side thereof, andexible joint means in said mandrel element between said pair of sealingmeans.

4. Apparatus adapted to be pumped through a pipe, said apparatuscomprising a mandrel element of a diameter smaller than the pipe stringthrough which it is to be pumped in an unsupported manner, at least apair of selectively expandable annular sealing means carried on saidmandrel in axially spaced relationship, separate fluid passage means insaid apparatus adjacent one end of each of said sealing means incommunication between the inside and outside thereof, 'the opening tosaid fluid passage means of one sealing means being positioned on theupstream side thereof when positioned in a 'How stream within a pipe,while that to the other sealing means is positioned on the downstreamside thereof, flexible joint means in said mandrel element between saidpair of sealing means, and connecting means at one end of said m-andrelelement for connecting said mandrel to another object within said pipe.

5. Apparatus adapted to be pumped through a pipe, said apparatuscomprising a mandrel element of a diameter smaller than the pipe stringthrough which it is to be pumped in an unsupported manner, at least apair of selectively expandable annular sealing means carried on saidmandrel in axially spaced relationship, separate uid passage means insaid apparatus adjacent one end of each of said sealing means incommunication between the inside and outside thereof, the opening tosaid fluid passage means of one sealing means being positioned on theupstream side thereof when positioned in a flow stream within a pipe,while that to the other sealing means is positioned on the downstreamside thereof, flexible joint means in said mandrel element between saidpair of sealing means, connecting means at one end of said mandrelelement for connecting said mandrel to another object within said pipe,and a fishing head secured to the other end of said mandrel element.

6. Apparatus adapted to be pumped through a pipe, said apparatuscomprising a mandrel element of a diameter smaller than the pipe stringthrough which it is to be pumped in an unsupported manner, at least apair of selectively expandable annular sealing means carried on saidmandrel in axially spaced relationship, each of said sealing meanshaving a portion thickened in crosssection adapted to contact the innerwall of said pipe string, separate fluid passage means in said apparatusadjacent one end of each to said sealing means in communication betweenthe inside and outside thereof, the opening of said uid passage means ofone sealing means being positioned on the upstream side thereof whenpositioned in a flow stream within a pipe, while that of the othersealing means is positioned on the downstream side thereof, flexiblejoint means in said mandrel element between said pair of sealing means,connecting means at one end of said mandrel element for connecting saidmandrel to another object within said pipe, and a fishing head securedtothe other end of said mandrel element.

References Cited in the ile of this patent UNITED STATES PATENTS 451,841Platt et al. May 5, 1891 971,042 Hill et al Sept. 27, 1910 2,221,775Boynton Nov. 19, 1940 2,789,645 Curnutt et al Apr. 23, 1957

